Many autoimmune conditions are believed to result from chronic inflammation as a consequence of the interaction of genetic and environmental factors in susceptible individuals. One common feature in some autoimmune diseases is a change in the glycan pattern of plasma immunoglobulins. The glycosylation pattern of the antibodies isolated from patients with ANCA-MPO (a kidney autoimmune disease) is being investigated to determine whether a similar trend is observed in individuals with other autoimmune disorders as we have seen before . The levels of digalactosylated structures and terminally sialylated glycoforms on the Fc portion of total IgG from active PR3-ANCA patient significantly increased during disease remission and regained glycosylation levels indiscernible from those in healthy controls. In contrast, Fc N-glycan levels of total IgG from MPO-ANCA patients did not correlate with disease activity. Notably, MPO-ANCA patients continued to exhibit a deficit of terminal sialic acid and galactose residues during disease remission and, therefore, Fc N-glycan levels never appeared similar to healthy controls. Structural and functional studies of the antigens of autoimmune diseases are necessary to increase our understanding of the pathogenesis of the disease. The function(s) of the primary autoantigen, LaSSB, associated with Sjogrens syndrome, a chronic rheumatic autoimmune disease that primarily targets the salivary and lacrimal glands, is unknown at this time, but the role of the LaSSB antigen is thought to be critical for understanding the mechanism of the development of autoimmunity. Structural and functional studies of this antigen are necessary to increase our understanding of the pathogenesis of Sjogrens syndrome. Structural studies involving chemical modification, oxidative footprinting, and H/D exchange in combination with mass spectrometric analyses have been used to gain information regarding the surface accessibility of amino acids in LaSSB. Collectively, these data provide useful information regarding the tertiary structures of LaSSB and has been used to help generate a structural model of the full-length LaSSB.